According to the study, published in the Journal of Experimental Psychology: General, researchers from Harvard University and the University of Texas, Austin looked into the role our hormones play in the bad decisions we make. As part of their study, they took 117 participants and asked them to complete a math test. Then, participants were asked to self-grade the test and report how many problems they got right. Researchers told participants that the more problems they solved correctly, the more money they would receive. Afterwards, the researchers collected saliva samples from the participants.

They found that people who had higher levels of testosterone and cortisol were more likely to lie about the number of problems they got right.

“Elevated testosterone decreases the fear of punishment while increasing sensitivity to reward” said Robert Josephs, UT Austin professor of psychology. “Elevated cortisol is linked to an uncomfortable state of chronic stress that can be extremely debilitating. Testosterone furnishes this courage to cheat, and elevated cortisol provides a reason to cheat.”

In short, the reproductive hormone testosterone, and the stress hormone cortisol play a two-part role in encouraging and enforcing cheating. Here's how it works: Hormone levels will first increase, which makes a person more susceptible to cheating. Then, their hormone levels will change to reinforce the behavior.

The study further found that people who cheated not only had lower levels of cortisol in their systems, but felt a reduction in stress after the test was done.

Cheaters come in all shapes and sizes. How can you possibly tell who’s going to cheat on you just by looking at them? Well, here’s what science says about certain body parts, and what they say about your likelihood of cheating — and being cheated on.

1. Blonde Women Are More Likely To Cheat

Do blondes have more fun? Apparently. According to a 2012 study conducted by Cheaterville.com, about 42 percent of the women using the cheating website were blonde. Redheads came in second, with 23 percent. Brunettes represented about 20 percent of the female population. Black-haired women were at 11 percent. The study found that hair color may have even led to a partner having an affair. It was found that eight percent of the female affair victims said that their SO asked them to change their hair color during the relationship.

2. But So Are Brown-Haired Men

The same study found that brown-haired men were most likely to cheat, making up about 40 percent of the site’s population. Black-haired men were second at 32 percent, followed by blondes at 20 percent, and redheads at five. However, the study did not account for balding, or temporary or permanent hair coloring.

3. Tall Dudes Are More Likely To Cheat

If you’re into the whole tall, dark, and handsome thing, be aware. According to a 2014 study conducted by IllicitEncounters.com, men who were over 5’10 were more likely to cheat in comparison to men under that height. Apparently, taller men have a sense of confidence about themselves that shorter guys don’t necessarily have, so they feel more protected and secure with themselves in doing whatever they want.

4. People With Longer Ring Fingers Are More Likely To Cheat

If you want to see how susceptible you are to cheating, just take a look at your hand. A study published earlier this year conducted by psychologists from Oxford University and Northumbria University looked at 600 men and women from both the US and Britain. They found that people with longer ring fingers were more likely to be promiscuous than those whose ring and index fingers were about equal lengths. The researchers attributed that to the amount of testosterone a person was exposed to in the womb. The people with longer ring fingers were likely to have been exposed to more testosterone.

5. Men With Large Feet

According to another Illicit Encounters study released in 2014, men who wear shoes larger than size 10 are three times more likely to have sex outside of a relationship than men whose shoe size range from seven to nine. The study, which consisted of 3,128 men, found that 22 percent of men with size 11 shoes said they went on the site to find sexual liaisons, while only four percent of men with size seven feet would consider cheating on their partners.

6. Penis Length

In a strange twist of events, a 2014 study published in PLOS One found that women were more likely to cheat on men who had bigger penises. According to scientists from the Center for Microbiology Research in Kisumu, Kenya, as well as Kenyatta University, the University of California, and the University of Alabama, 545 Kenyan women were questioned about their relationships. It was found that the women who cheated on their husbands found their husbands’ penises to be too big. According to the study, the women disliked the pain and discomfort that accompanied their partner’s size.

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